Vertical OTFT Structure With Donor-Acceptor Polymer for High Current
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Solution Overview
Problem
Organic field-effect transistors (OFETs) exhibit low current output and mobility due to weak wavefunction overlap and disorder in thin films, requiring high operating voltages and being unstable due to surface effects, limiting their frequency and stability.
Innovation Solution
The development of polymer compositions incorporating heterocyclic organic compounds, such as fused thiophene compounds, which are more soluble and processable, and the use of a vertical transistor design with a donor-acceptor organic semiconductor structure, allowing for high current densities at low voltages and improved stability without the need for encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional horizontal OFET structure is used, then device fabrication is simplified, but current output is low and operating voltage must be high
Solution Approach 1:
The patent transitions from a conventional horizontal planar FET structure to a vertical FET structure, changing the spatial arrangement of source, drain, and gate electrodes from a two-dimensional plane to a three-dimensional vertical configuration. This dimensional change enables improved current output while maintaining fabrication simplicity through solution-processing techniques.
2Device complexity
If conventional OFET structure is used, then device structure is simple, but carrier mobility is low and operating frequency is limited
Solution Approach 1:
The patent changes the structural parameters of the FET by adopting a vertical configuration with source and drain electrodes positioned at opposite ends of the channel in the vertical direction, rather than laterally adjacent. This parameter change, combined with the use of donor-acceptor organic semiconductor materials, achieves high carrier mobility while keeping the device structure relatively simple.
3Area of stationary object
If conventional OFET structure is used, then device footprint is large, but current density is insufficient
Solution Approach 1:
By transitioning to a vertical FET structure, the patent reduces the lateral footprint of the device while concentrating the current flow in the vertical direction. The source and drain electrodes are positioned vertically above and below the channel, enabling high current density within a compact area suitable for high-resolution display applications.
4Ease of manufacture
If thin film semiconductor layer is used, then solution processing is enabled, but wavefunction overlap is weak and mobility is low
Solution Approach 1:
The patent employs donor-acceptor organic semiconductor materials with specific molecular structures that combine electron-donating and electron-accepting units. This composite molecular architecture enhances wavefunction overlap and charge carrier mobility within the thin film, while maintaining solution processability through appropriate solvent selection and deposition techniques.
Data Source
AI summary
Devices include a substrate, a collector layer, and an emitter layer positively biased relative to the collector. Devices further include a semiconductor layer located between the collector and the emitter. The semiconductor layer includes an organic semiconductor polymer with a donor-acceptor structure.